Forfar is one project in a long-standing relationship. OCS has worked with Scottish Water Horizons since 2016, contributing to more than 40MW of solar PV installed across Scottish Water’s estate. That work has helped make Scottish Water one of the largest public-sector contributors to renewable energy generation in Scotland, through solar, battery storage, and hydro schemes delivered at live operational sites.
At the Forfar Wastewater Treatment Works, more than 600 solar panels now generate renewable electricity on site, cutting reliance on the grid and supporting Scottish Water’s journey to net zero. OCS Energy Services delivered the project, a commercial solar panel installation, in partnership with Scottish Water Horizons.
Solar Power at Forfar in Numbers
The new solar array is helping Forfar Wastewater Treatment Works generate renewable electricity on site, reduce reliance on the grid and cut carbon emissions.
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283.95
kWp Solar Capacity Installed at Forfar
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253913
kWh Energy Generated Each Year
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90.3%
Renewable Energy Used Directly on Site
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71845
kg CO₂e Emissions Avoided Each Year
The Challenge
Forfar Wastewater Treatment Works provides a vital service to thousands of customers across Angus. Treating wastewater takes a lot of energy. Like every operational site, it is exposed to the ups and downs of grid electricity prices, and every unit drawn from the grid carries a carbon cost.
Scottish Water wanted to generate more of that power on site: lowering running costs, strengthening resilience against price volatility, and cutting carbon emissions in line with its target of reaching net zero by 2040.
The Approach
Working with Scottish Water Horizons, OCS Energy Services designed and installed a 283.95 kWp ground-mounted solar array. The system uses 631 panels rated at 450W each, laid out to make the most of the available land beside the works.
OCS held responsibility for design, installation, and grid compliance, connecting the array to the site’s existing supply and commissioning it for long-term operation. The installation follows the standard set across the wider Scottish Water Horizons framework, where OCS acts as both Principal Designer and Principal Contractor and every connection is approved by the local network operator before work begins.
The Outcomes
The array generates around 253,913 kWh of renewable electricity a year. Of that, 229,184 kWh, or 90.3 per cent, is used directly on site, so almost everything produced goes straight into running the works. Solar output rises and falls with the seasons, but with more than nine-tenths consumed on site, very little is lost.
The solar supply now offsets around 20 per cent of the site’s electricity consumption and avoids roughly 71,845 kg of CO2 each year. For Forfar, that means lower operating costs, better protection from energy price swings, and a measurable cut in carbon that will continue for years to come.
It is great to see this project completed at Forfar Wastewater Treatment Works, helping to reduce operating costs at the site and strengthening energy resilience. By generating more of our power onsite, we are better protected from energy fluctuations, while also reducing carbon emissions. We are continuing to deliver a variety of renewables projects at Scottish Water sites across the country as we work towards achieving net zero by 2040.
Project Manager, Scottish Water Horizons
The wastewater treatment works here in Forfar provides a vital service to thousands of customers and it is really positive that the site will now be producing and making use of its own renewable energy for years to come.
Operational Team Leader, Scottish Water
Reliable energy sits at the heart of effective site operations. Working with Scottish Water Horizons and Scottish Water, this project in Forfar shows how onsite generation can strengthen resilience, give teams greater control over energy use, and support more stable operating costs, while reducing carbon emissions.
Managing Director – Energy, OCS UK